EV range dropped after up-sized to 17" wheels

Yeah there is a penalty, going to 17", more so with something like the 3rd gen 17" OEM rims, real porkers at 24 pounds apiece. Both the weight and the wider tire are factors. It's not terrible though, you adjust.

Assume you meant to say 215/45R17?

 

They probably aren't low rolling resistance tires either. Heavier wheels and wider, less efficient tires are a certain recipe for reduced range due to more energy demand.

 

What are the revs/mile for the new wheel tire combination?

Bob Wilson

 

I usually go to TireRack whose list of Continental tires does not include "Continental Control Contact." Tirerack is very good about having the full specifications including the revs/mile. I then checked the Continental web site but could not find "rev/mile", the spec we need.

Can you provide a benchmark of GPS/mile-marker vs tripmeter distance? We can compare your numbers to the stock tire and determine if they are larger, same, or smaller revs/mile.

As tires wear down, there are reports of an initial 'break-in' period of several thousand miles before the tires normalize. I've personally never seen this because as soon as I leave the tire shop, I fully inflate them to maximum sidewall.

Bob Wilson

 

Toyota advocates (and supplies, on models with stock 17" wheels) 215/45R17, which has slightly smaller OD than 195/65R15.

We alternate between those two sizes, 17" stock all seasons and 15" snow tires, and they are quite close.

Going to 225 is a bit unorthodox, WILL reduce revs per mile (skew the odo) and increase rolling resistance. Slightly increases wind resistance too?

 

What's not smart about it? If the car is 20% less efficient, it's going to go 20% shorter on a charge. The car should report this as it represents reality.

 

Ok, close enough. Try max sidewall pressure? You can always reduce pressure.

Bob Wilson

 

I doubt the RPM of 1 per mile is significant enough to change anything, but the non-LRR tires will be a penalty, and the extra pound of weight at the wheel is going to make a difference. New tires are at their least efficient point and will get better efficiency as they wear, a tire is at it's most efficient point when it is due to be replaced. A lot of people experience a slight mileage drop when changing tires because of this.

 

I can't say for certain how much this would effect your gas mileage but it's also possible that by switching to a 17" wheel with a heavier tire from a 15" wheel, you've increased the torque required to overcome rotational inertia (start the wheel turning). As weight of a wheel moves away from the hub, it increases the amount of torque required to turn the wheel. So if your tires weighed exactly the same, the 15" would be easier to turn because it's weight would be more toward the center of the hub. Your new tires are about 2 lbs heavier and but present a lower profile (more of the weight is to the outside of the wheel). Your overall wheel/tire combo is heavier only by a pound, but more of the weight is away from the hub. It means the torque required to turn the wheel is greater. This is over exaggerated but think of a playground merry-go-round. If the kids are sitting in the middle of the merry-go-round when you start to push it, it's easy to start it turning. If they move to the outside before you try to start it turning, it takes much more work to get it turning to the same speed.

If you normally drive short, stop and start trips, your new wheels will be less efficient as you'll have to overcome the greater inertia each time you start. However, if you do a lot of highway driving (very little stopping and starting), it might increase fuel economy because you only overcome the inertia once. Once it gets going, it won't require as much energy to keep it going.

 

The rotational inertial of all four wheels together is minuscule compared to the translational inertia of the entire car.